Itachi (Shonen)
Mystery:- Uchiha Shuriken Jutsu (chakra usage =20) Hurls shuriken at the whole enemy team causing damage and repulse to the selected Character

(Battlefield cooldown - 1 round, mystery Cooldown- 1 round)

Standard:- Taijutsu Attack - performs a basic taijutsu attack, fixed probability of causing highfloat

Chase : - Fireball jutsu- upon 10 combo causes igition to 3 untis in the opponets team, if this chase is executed after the mystery the mystery of this unit will suffer no cooldown.

Chase: Shuriken Jutsu Blindspot Strike:- Chases a high floated unit causes repulse

Passive :- Will of Fire- Increases the Attack and Defence of 3 konoha ninja in the lineup by 50 %, lasts 3 rounds. If a hokage is present in the lineup this buff will last 5 rounds.

Passive:- Sharingan- If the opponents lineup consists of any secret jutsu/ Kekkei genkai/ dojutsu, lowers the defence and resistance of the opponents lineup by 40 %.

the reason itachi has all these abilities is cuz he was OP even as a kid. and as hiruzen had quoted after being ressurrected by orochimaru " Itachi despite being a boy was never bound to the chains of the clans even as a 7 year old his mind was on par with that of a hokage"
The mystery is the one shown because itachi's speciality was shuriken jutsu and fireball jutsu ( when he imitates a master level fireball jutsu of Fugaku Uchiha in his first attempt)
The sharingan passive is there cuz itachi unlocked his sharingan quite eaarly in his childhood and had mastered it by the age 7.